Human brain stem cells grown in rats

STEM cells from the human brain that were transplanted into the brains of newborn rats have matured and are able to function just like native rat cells. The breakthrough demonstrates the potential for people with brain damage, caused by epilepsy or Parkinson's for example, to use their own brain stem cells as a treatment.

The key finding was that the adult stem cells had the ability to turn into all types of brain tissue in the rats. This includes the neocortex, which deals with higher processing, and the hippocampus, involved in memory and spatial awareness.

"We're showing the most dramatic integration of human adult neurons into rat brains," says Steven Roper of the University of Florida in Gainesville, who carried out the work.

Roper extracted the adult stem cells from tissue he had taken from a teenage girl's brain as part of standard epilepsy surgery. He and his colleague Dennis Steindler multiplied the cells in the lab, then genetically engineered them so that they would glow green under ultraviolet light.

Next, they injected groups of the cells into the brains of newborn rats. Three weeks later, they examined the rats' brains and found green cells throughout. "The cells matured into neurons appropriate for each part of the brain they reached," says Roper.

The pair also found that the cells were fully functional and able to signal to rat neurons, as shown by lab tests monitoring the cells' electrical activity. The work will be presented at this week's meeting of the American Epilepsy Society in San Antonio, Texas.

The hope, says Roper, is that when people with brain damage undergo surgery, it may be possible to isolate stem cells from excised tissue. These could then be multiplied in the lab, turned into cell types from which the person might benefit, then returned to the brain.

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